1. Technical Field
This invention relates to a high bulk tissue web and method of making and processing a high bulk tissue web. In one aspect, this invention relates to a method of making a high bulk tissue web wound on large diameter parent rolls, unwound for finishing operations, and subsequently rewound.
2. Background
A large diameter manufactured parent roll of bathroom tissue or kitchen toweling can be unwound for finishing operations, such as for calendering, embossing, printing, ply attachment, perforating, or for a combination of two or more finishing operations. The finished bathroom tissue or kitchen toweling then can be rewound into a retail-sized log or roll.
At the time a parent roll runs out, the spent shaft or core can be removed from the machine, and a new roll moved into position by an overhead crane or extended level rails.
Core plugs can support the parent roll on an unwind stand with unwinding power coming from a belt or belts operating on a parent roll surface.
A surface-driven unwind system is not suitable for all types of tissue webs because of a decrease in a machine direction stretch, a reduction of bulk, or damage to the surface of the tissue web, particularly in high bulk tissue webs.
Center driven unwind systems can unwind film.
A down time associated with a parent roll change represents a substantial reduction in total available run time.
The manpower required to change a parent roll reduces the efficiency of a rewinder line and reduces the productivity of neighboring operations when workers are borrowed for roll changes.
Where a finishing unit bonds the expiring web and the new web together, the webs can be threaded manually and advanced. The manual operation reduces efficiencies significantly.
Consequently, a parent roll change reduces the maximum output obtained from a rewinder line and reduces the productivity of neighboring operations as well.
Accordingly, a method for making and processing a web is needed for maintaining preferred characteristics of the web, such as the bulk and the uniformity of the web. A method for making and processing a web also is needed for reducing the time the machine is stopped, to increase overall efficiency, and to provide safety for all personnel.
The apparatus and method of the present invention for making and processing a high bulk tissue web include depositing an aqueous suspension of papermaking fibers onto an endless forming fabric to form a web, drying the web to form a dried web having a bulk of 9.0 grams per cubic centimeter or greater, winding the dried web to form a plurality of large diameter parent rolls each comprising a web wound on a core, and transporting the parent rolls to an unwind stand having torque transmitting clamping means for engaging opposite end surfaces of the parent rolls. A backing plate is operably connected to and rotatable with an unwind shaft connected to an electric drive. An inflatable bladder is mounted on the backing plate. The clamping means engage a first parent roll by inflating the bladder such that the opposite end surfaces of the roll are sandwiched between the side clamping mechanisms for partially unwinding the first parent roll using a variable speed drive operably associated with the clamping means. The partially unwound first parent roll is rotatably supported on a core placement table adapted to receive the partially unwound first parent roll from the clamping means. The torque transmitting clamping means engage a second parent roll, and a leading end portion of the web on the second parent roll is joined to a trailing end portion of the partially unwound first parent roll to form a joined web without glue. The joined web is rewound into smaller diameter rolls suitable for retail sizing.
In one aspect, the leading end portion of the web on the second parent roll is transported with a thread-up conveyor.
In one aspect, the leading end portion of the web on the second parent roll is transported with vacuum means operably associated with an endless screen belt means with decreasing amounts of vacuum as the web is transported over the endless screen belt means.